Automotive vehicles are increasingly being equipped with collision warning systems that warn the driver of the vehicle of objects that pose an obstruction to the vehicle. Collision warning systems typically include one or more sensors, such as radar sensors and cameras, for sensing the presence of an object in a coverage zone, usually forward or rearward of the host vehicle. While vehicles are typically equipped with side view mirrors for viewing a portion of the side of the vehicle, it should be appreciated that many vehicles exhibit an unviewable area which is commonly referred to as a blind spot. In addition to sensing objects forward and rearward of the vehicle, it is also desirable to sense objects that may be located proximate the side of the host vehicle, particularly in the blind spot, to warn the driver of any obstructions, especially when changing lanes.
A number of detection systems have been proposed for detecting objects in a vehicle blind spot. Many of the proposed side detection systems employ various types of sensors for detecting an object and alerting the driver of the host vehicle of the presence of an object in the blind spot. Examples of proposed detection systems for detecting objects in a blind spot of a vehicle are disclosed in U.S. Pat. No. 5,668,539 and U.S. Patent Publication No. 20020126002, both of which are hereby incorporated herein by reference. The approaches disclosed in the aforementioned patent documents generally employ a plurality of infrared sensors, such as thermopile sensors, to detect changes in a thermal scene along the side of a host vehicle to detect the presence of a thermal emitting object, such as another automobile, in the blind spot of the host vehicle. These prior techniques employ identical sensors positioned at predetermined locations along the side of the host vehicle such that the forward-most sensor is aimed in a particular direction to receive a thermal image from a specific area, and a second sensor is located further aft of the host vehicle and is positioned to view the same area, some predetermined time period after the first sensor as the host vehicle moves forward. By knowing speed of the host vehicle, a microcontroller determines the amount of time shift that is necessary to have data from the same physical area of two different points in time. If there is a temperature increase in the second thermal image, then it is assumed to be heat emitted from a vehicle. The heat could be heat reflected from the road from under the vehicle or heat generated at the interface of the road and tires of the vehicle.
While the aforementioned approaches provide a means to detect heat-emitting objects in a blind spot of the host vehicle, such approaches generally do not adequately detect such objects while the host vehicle is stopped. Thus, in a multi-lane roadway, if another vehicle moves into the blind spot of the host vehicle while the host vehicle is stopped, these prior approaches may not detect the object vehicle in the blind spot of the host vehicle. It is therefore desirable to provide for a detection system for detecting a heat-emitting object relative to the host vehicle when the host vehicle is stopped.